Elevation control for excavator



May 26, 1970 J. H. HYLER ELEVATION CONTROL FOR EXCAVATOR 2 Sheets-Sheet 1 Filed Aug. 14. 1967 & INVENTOR JOHN H. HYLER BY ANDREW J. BECK y 26, 1970 J. H. HYLER 3,513,916

ELEVATION CONTROL FOR EXCAVATOR Filed Aug. 14. 1967 2 Sheets-Sheet 2 wkk INVENTOR JOHN H. HYLER BY ANDREW J. BECK United States Patent Office 3,5 13,9 16 Patented May 26 1970 3,513,916 ELEVATION CONTROL FOR EXCAVATOR John H. Hyler, Peoria, Il]., assignor to Westinghouse Air Brake Company, Peoria, 111., a corporation of Pennsylvania Filed Aug. 14, 1967, Ser. No. 660,397 Int. Cl. A01b 63/111 US. Cl. 1724 22 Claims ABSTRACT OF THE DISCLOSURE A control for reducing gouging of a hydraulically actuated bulldozer into a surface being excavated, the control including a non-load supporting gage arm pivotally mounted on the bulldozer push arm or moldboard. The gage arm is adapted to contact the surface being excavated and is connected to a servo means for directing fluid to the bulldozer lift cylinder means to rapidly vertically adjust the bulldozer in response to gage arm movement to maintain constant relative longitudinal alignment of the bulldozer and the gage arm. In this manner gouging is circumvented by maintaining a constant depth of cut. A manually operated valve for actuating a piston is provided to vertically adjust the gage arm and simultaneously override the action of the gage arm to vertically adjust the bulldozer.

FIELD OF INVENTION This invention relates to bulldozers and, more specifically, to bulldozers including auxiliary elevation controls for the excavating scraper blade.

DESCRIPTION OF THE PRIOR ART Heretofore, various types of auxiliary automatic elevation controls for excavators, in addition to conventional manually controlled power lift means, have been available. Such controls vary in complexity from elaborate energy plane controls such as disclosed in the Bensinger 2,796,685 patent, to artificial reference plane or grade wire sensing controls as disclosed in the Thomas 3,221,425 patent, to self-containing pendulum-type controls as disclosed in the Colee 2,904,911 patent, to land leveler-type controls as disclosed in the Curlett 3,057,092 patent, to simple ground contacting auxiliary support shoes or wheels such as disclosed in the Lull 2,959,876 patent. These various types of elevation controls have not always proved to be satisfactory for preventing bulldozer gouging because such devices have either been ineffective or too complex.

Gouging may be considered to be an accidental, shortterm elevational variation of the bulldozer blade as caused by a sudden encounter with a change of material resistance or contour which results in a sucking action of the dozer blade to draw the same downwardly. To circumvent gouging or washboarding, a dozer operator must be experienced to react quickly without over-reacting by raising the dozer too high. This problem is particularly emphasized when high speed wheeled or rubber-tired tractors are utilized because, as the tractor bounces up and down or the rubber tires flex under load, bulldozer elevation rapidly varies.

In this light, the previously mentioned energy plane and grade wire type controls have not proved to be practical because reliance is placed on an artificial reference plane which must be specially provided. Additionally, such devices operate to maintain absolute elevation without regard to depth of cut and, while helpful in generally maintaining a grade, are not necessarily helpful in eliminating short-term elevational variations. Land leveler and pendulum-type controls merely average out the various contour changes encountered throughout the length of the vehicle without maintaining constant depth of cut. Simple auxiliary supports have not always been effective depending upon the size of a depression encountered relative to the support surface. Additionally, such supports appreciably increase the horsepower required for the excavating operation because of the drag created by the auxiliary support and, of course, do not limit upward blade movement. Finally, certain agricultural implements, such as plows, are sometimes equipped with constant depth of cut controls, such as disclosed in the Rue 2,913,878 patent, but such controls have found no application in preventing bulldozer gouging.

SUMMARY OF THE INVENTION It is a general object of the present invention to provide an auxiliary elevation control for an excavator which minimizes or circumvents the problems heretofore noted and reduces gouging.

In achieving this general object, the present invention provides a scraper blade adapted to be mounted on a vehicle and extend transversely of the direction of travel, the scraper blade comprising a generally vertically extending moldboard assembly having a cutting edge on the lower end thereof, and a frame assembly for supporting the moldboard assembly. Power lift means attached to the moldboard or frame assembly for vertically adjusting the moldboard assembly are provided. Gage means are freely movably supported on one of said assemblies in a nonload bearing relationship thereto, the lower end of the gage means being adapted to contact the surface being excavated. A control means is operatively connected to the gage means and the power lift means to rapidly vertically adjust the moldboard in response to movement of the gage means to thereby maintain the longitudinal alignment between the lower ends of the gage means and the cutting edge.

The control means may further include overriding means to override the action of the gage means to simul taneously vertically adjust both the gage means and the moldboard assembly.

BRIEF DESCRIPTION OF THE DRAWINGS In describing the invention, reference will be made to the accompanying drawings in which:

FIG. 1 is a side elevational view of a wheel or rubber tired tractor, portions of which are shown in phantom line, on which is mounted a bulldozer including an elevation control according to the present invention, the hydraulic system thereof being schematically illustrated; and

FIG. 2 is a schematic diagram of a hydraulic system of the elevation control shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring in more detail to FIG. 1 of the drawings, a conventional wheel or rubber tired tractor 10 having an operators compartment 12 is shown equipped with a conventional bulldozer 14 on the forward end thereof. The bulldozer includes an elongated moldboard or blade assembly 16 pivotally supported on the tractor by a push arm or frame assembly 18 including a pair of push arms fixed to the rear end of the moldboard assembly. A cutting edge 19 is fixed to the lower forward face of the moldboard assembly 16. A hydraulic system 20 is pro vided for actuating a bulldozer power lift or hoist assembly 22 including at least one pivotally mounted doubleacting hydraulic cylinder 24, the lower end of the rod 26 which is pivotally connected to the upper end of the moldboard assembly 16.

With reference to FIGS. 1 and 2 of the drawings, the hydraulic system 20 comprises a fluid reservoir ortank 28 connected by a conduit 30 to an engine-driven pump 32. The pressure side of the pump 32 is connected by a conduit 34 to a manually operable two-way spool-type, selector valve 36. The selector valve 36 may be selectively placed in fluid communication with a bulldozer control valve 38 or an elevation control valve 40.

The bulldozer control valve 38 is of a conventional type and includes a four-way spool-type valve 42 adapted to be moved to dozer raise, lower, hold and float positions by a control lever 44 mounted adjacent the operators platform 12. A generally conventional hydraulic circuit 46 including pressure relief and check valves 48 and 50, respectively, is provided to place the bulldozer control valve in fluid communication with the selector valve 36 and pump 32. Additional conduits 52 and 54 are provided to place the bulldozer control valve 38 in fluid communication with the piston and rod ends, respectively, of the hydraulic cylinder 24.

Both the selector and elevation control valves, 36 and 40, respectively, are provided with manual control levers, not shown, adjacent the bulldozer control lever 44. A pair of conduits 56 and 58 are provided to place the selector valve 36 in fluid communication with the elevation control valve 40 and a servo control valve 60. Both the elevation control valve 40 and the servo control valve 60 include three-way spool valves 61 and 62 adapted to be moved to raise, lower, and hold positions. A pair of conduits 63 and 64 connect the servo control valve 60 to the piston and rod ends, respectively, of the cylinder 24.

According to the present invention, a gage assembly 66 is pivotally mounted on the forward end of the push arm assembly 18 adjacent and, to the rear of, the moldboard assembly 16. The gage assembly 66 comprises a spring biased, cam-shaped gage arm 68, an intermediate portion of the forward end of which is pivotally mounted on the push arm assembly 18 by a pin 70. The rear end of the gage arm 68 is extended in a vertical direction and includes a shoulder 72 adapted to contact a stop 74 on the outboard face of the push arm assembly 18 to limit movement of the gage arm 68 in a downwardly or clockwise direction. The upper forward end of the gage arm 68 is pivotally connected to a link 76, the rear end of which is operatively connected to the spool valve 61 of the servo control valve assembly 60. Any suitable spring means 78 (FIG. 2) may be provided to urge the gage arm 68 in a downward or clockwise direction.

Operation of the present invention to circumvent gouging is as follows: Initially, the operator may position the moldboard assembly 14 as desired by manual operation of the bulldozer control valve 38. Subsequent repositioning of the selector valve 36 redirects the flow from the pump 32 from the bulldozer control valve 38 to the servo control valve assembly 60. Upon forward movement of the vehicle, should the rubber tires of the vehicle flex or the moldboard assembly encounter a change in resistance or contour of material that tends to suck the moldboard assembly in a downward direction, such undesired downward movement of the moldboard assembly will cause the gage arm 68 to oppositely move in a counterclockwise or upwardly direction thereby moving the spool valve 61 of the servo control valve assembly 60 in a direction towards the left, as shown in FIG. 2 of the drawings. In such a position, fluid flow from the pump 32 is directed through the conduit 64 to the rod end of the cylinder 24 to thereby rapidly adjust the moldboard assembly in an upward direction to a degree that will compensate the apparent. Similarly, should the moldboard assembly be urged in an upward direction by an obstruction or by would move in a clockwise or downward direction for a reverse effect on the system to adjust the moldboard assembly in a downward direction to a degree to rapidly compensate for the initial upward movement.

To vertically adjust the gage arm 68 or to override the action thereof for independently adjusting bulldozer elevation, the present invention includes a servo valve hydraulic cylinder 80 placed in fluid communication with the elevation control valve assembly 40 by conduits 81. The exposed rod end 82 of the hydraulic cylinder 80 may be mechanically connected to the servo control valve assembly 60 or spool valve 61 by any suitable mechanical linkage 84 to facilitate changing the position of the spool valve 61 fore and aft. Manual operation of the elevation control valve 40 to either a raise or lower position results in corresponding movement of the piston 80, movement of the servo spool valve 61, and corresponding pivotal movement of the gage arm 68. In this manner, an operator may instantly make any suitable adjustment in the elevation of the moldboard assembly 16 and, as these adjustments are made, the gage arm 68 is correspondingly and simultaneously adjusted.

It should be appreciated that while a mechanical link 84 is disclosed for movement of the servo spool valve 61 by the hydraulic cylinder 80, such adjustment may be achieved by other means such as direct fluid actuation and the like. Further, certain of the advantages afforded by the present invention may be attained by interposing the hydraulic cylinder 80 between the gage arm 68 and link 78, or to do away with power adjustment entirely and rely on a manual fore and aft adjustment.

Still further, although a single gage assembly for a bulldozer is disclosed, in some instances it may be desirable to provide each bulldozer push arm with such a gage assembly.

In describing the present device, reference has been made to a preferred embodiment, it should be appreciated by one skilled in the art that various additions, deletions and modifications may be made which fall into the scope of the present invention which is to be ascertained from the following claims:

What is claimed is:

1. A bulldozer blade movably mounted on a vehicle and extending generally transversely of the direction of travel, said bulldozer blade comprising:

an elongated, generally vertically extending moldboard assembly having a cutting edge on the lower end thereof;

a push arm assembly rigidly fixed to said moldboard assembly;

means for pivotally attaching said push arm assembly to said vehicle;

power lift and control means mounted on the vehicle and operatively connected to said moldboard assembly for selectively vertically adjusting said moldboard assembly relative to the vehicle for varying the depth of cut of said cutting edge;

gage means freely movably supported on the forward end of said push arm assembly in non-load bearing relationship thereto, the lower end of said gage means in longitudinal alignment with said cutting edge and adapted to contact the surface being excavated; and

second control means operatively connected to said gage means and in fluid communication with said power lift and control means to rapidly vertically adjust said moldboard assembly in response to movement of said gage means to thereby maintain the longitudinal alignment between said lower ends of said gage means and said cutting edge.

2. A bulldozer blade according to claim 1, said second control means further including hydraulic overriding means for overriding the action of said gage means to vertically adjust said moldboard assembly.

3. A bulldozer blade according to claim 2 wherein said overriding means simultaneously vertically adjusts said moldboard assembly and said gage means relative to said moldboard assembly.

4. A bulldozer blade according to claim 3 wherein said gage means further comprises a gage arm pivotally supported on said push arm assembly, and servo means in fluid communication with said selector valve means and said hydraulic cylinder means.

5. A bulldozer blade according to claim 5 wherein said overriding means further includes a manually operable second control valve means in fluid communication with said selector valve means, second hydraulic cylinder means in fluid communication with said second con trol valve means, and means operatively connecting said servo means to said second hydraulic cylinder means to move the servo means fore and aft relative to said push arm assembly.

6. A bulldozer blade according to claim 5 wherein said gage arm further comprises a spring loaded cam shaped arm, an intermediate portion of which is pivotally connected to said push arm assembly, an upper end of which is pivotally connected to said servo means, and a rear end of which includes stop means cooperating with corresponding stop means on said push arm assembly to limit gage arm movement in a downward direction.

7. A bulldozer blade according to claim 2 wherein said power lift and control means further includes a fluid pump adapted to be driven by the vehicle engine, manually operable selector valve means in fluid communication with said pump, manually operable control valve means in fluid communication with said selector valve means, and hydraulic cylinder means pivotally connected to said moldboard assembly and in fluid communication with said control valve means.

8. A bulldozer blade movably mounted on a vehicle and extending generally transversely of the direction of travel, said bulldozer blade comprising:

an elongated, generally vertically extending moldboard assembly having a cutting edge on the lower end thereof;

a push arm assembly rigidly fixed to said moldboard assembly;

means for pivotally attaching said push arm assembly to said vehicle;

power lift and control means mounted on the vehicle and operatively connected to said moldboard assembly for selectively vertically adjusting said moldboard assembly relative to the vehicle for varying the depth of cut of said cutting edge;-

gage means freely movably supported on said moldboard assembly in non-load bearing relationship thereto, the lower end of said gage means in longitudinal alignment with said cutting edge and adapted to contact the surface being excavated; and

second control means operatively connected to said gage means and in fluid communication with said power lift and control means to rapidly vertically adjust said moldboard assembly in response to movement of said gage means to thereby maintain the longitudinal alignment between said lower ends of said gage means and said cutting edge.

9. A bulldozer blade according to claim 8, said second control means further including overriding means for overriding the action of said gage means to vertically adjust said moldboard assembly.

10. A bulldozer blade according to claim 9 wherein said overriding means simultaneously vertically adjusts said moldboard assembly and said gage means relative to said moldboard assembly.

11. A bulldozer blade according to claim 9 wherein said power lift and control means further includes a fluid pump adapted to be driven by the vehicle engine, manually operable selector valve means in fluid communication with said pump, manually operable control valve'means in fluid communication with said selector valve means, and hydraulic cylinder means pivotally connected to said moldboard assembly and in fluid communication with said control valve means.

12. A bulldozer blade according to claim 9 wherein said power lift and control means further includes a fluid pump adapted to be driven by the vehicle engine, maniually operable selector valve means in fluid communication with said pump, manually operable control valve means in fluid communication with said selector valve means, and hydraulic cylinder means pivotally connected to said push arm assembly and in fluid communication with said control valve means.

13. A bulldozer blade according to claim 11 wherein said gage means further comprises a gage arm pivotally supported on said moldboard assembly, and servo means in fluid communication with said selector valve means and said hydraulic cylinder means.

14. A bulldozer blade according to claim 13 wherein said overriding means further includes a manually operable second control valve means in fluid communication with said selector valve means, second hydraulic cylinder means in fluid communication with said second control valve means, and means operatively connecting said servo means to said second hydraulic cylinder means to move the servo means fore and aft relative to said push arm assembly.

15. A bulldozer blade according to claim 14 wherein said gage arm further comprises a spring loaded cam shaped arm, an intermediate portion of which is pivotally connected to said moldboard assembly, an upper end of which is pivotally connected to said servo means, and a rear end of which includes stop means cooperating with corresponding stop means on said moldboard assembly to limit gage arm movement in a downward direction.

16. A bulldozer blade according to claim 12 wherein said gage means further comprises a gage arm pivotally supported on said moldboard assembly, and servo means in fluid communication with said selector valve means and said hydraulic cylinder means.

17. A bulldozer blade according to claim 16 wherein said overriding means further includes a manually operable second control valve means in fluid communication with said selector valve means, second hydraulic cylinder means in fluid communication with said second control valve means, and means operatively connecting said servo means to said second hydraulic cylinder means to move the servo means fore and aft relative to said push arm assembly.

13. A bulldozer blade according to claim 17 wherein said gage arm further comprises a spring loaded cam shaped arm, an intermediate portion of 'which is pivotally connected to said moldboard assembly, an upper end of which is pivotally connected to said servo means, and a rear end of which includes stop means cooperating with corresponding stop means on said moldboard assembly to limit gage arm movement in a downward direction.

19. A bulldozer blade according to claim 2 wherein said power lift and control means further includes a fluid pump adapted to be driven by the vehicle engine, manually operable selector valve means in fluid communication with said pump, manually operable control valve means in fluid communication with said selector valve means, and hydraulic cylinder means pivotally connected to said push arm assembly and in fluid communication with said control valve means.

20. A bulldozer blade according to claim 19 wherein said gage means further comprises a gage arm pivotally supported on said push arm assembly, and servo means in fluid communication with said selector valve means and said hydraulic cylinder means.

21. A bulldozer blade according to claim 20 wherein said overriding means further includes a manually operable second control valve means in fluid communication with said selector valve means, second hydraulic cylinder means in fluid communication with said second control valve means, and means operatively connecting said servo means to said hydraulic cylinder means to move the servo means fore and aft relative to said push arm assembly.

22. A bulldozer blade according to claim 21-wherein said gage arm further comprises a spring loaded cam shaped arm, an intermediate portion of which is pivotally connected to said push arm assembly, an upper end of which is pivotally connected to said servo means, and a rear end of which includes stop means cooperating with corresponding stop means on said push arm assembly to limit gage arm movement in a downward direction.

, References Cited UNITED STATES PATENTS 10 ROBERT E. PULFREY, Primary Examiner S. C. PELLEGRINO, Assistant Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,513,916 May 26, 1970 John H. Hyler It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 10, claim reference numeral "5" should read 4 Signed and sealed this 12th day of January 1971.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner oflPatents 

